1. Field of the Invention
This invention relates in general to automatic machines which have a fixed delay time and in particular to a speed compensated timing circuit for a machine.
2. Description of the Prior Art
In a process line such as a sheeter operation, there often exists functions which have a fixed delay time between the time of actuation of a device and the reception of the control signal. If the process line always runs at a fixed speed and if the delay is known, it is very simple to anticipate the delay in the actuated device by actuating the system early enough to compensate for the known fixed delay time.
An example of this type of delay would be, for example, the combined times to sense a moving sheet and then energize a solenoid valve, pressurize an air cylinder, and the time for the cylinder to move a piston a known distance to overcome the system's inertia.
However, if the system is to operate at different speeds, the actuation of the system must occur earlier with respect to the web position as, for example, in a sheeter machine at higher web speeds than at lower web speeds.